Method for determining the resolution of blood glucose

ABSTRACT

The present invention provides a method for calculating the resolution of blood glucose which corresponding with the peak value of the rising curve. The average peak value is obtained from calculating the plurality of peak value, which determined after the pre-setting sampling time. Then, the average peak value is calculated with the resistance of the measuring circuit, reference resistance, and reference voltage to obtain the resolution of the blood glucose. Furthermore, the mapping table can be fabricated by the different height of maximum peak value and outputted voltage in different presetting sampling time, such that the resolution of blood glucose can be obtained in different outputted voltage values.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a method for determining theresolution of blood glucose, and more particularly to a peak value ofthe rising curve method to determine the resolution of the bloodglucose.

2. Description of the Prior Art

In the past, many systems have been developed for monitoring bloodcharacteristics. For example, devices have been developed which arecapable of determining such blood characteristics as blood oxygenation,blood glucose concentration. However, significant difficulties have beenexisted when attempting to specifically determine blood glucoseresolution accurately using noninvasive blood monitoring systems such asby means of spectroscopic measurement.

The difficulty in determining blood glucose resolution accurately may beattributed to several causes. Firstly, within the bloodstream, the bloodglucose is typically found in very low resolution (e.g., on the order of100 to 1000 times lower than hemoglobin) so that such low resolutionsare difficult to detect noninvasively, and require a very high signal-tonoise ratio. Additionally, with spectroscopic methods, the opticalcharacteristics of glucose are very similar to those of water that isfound in a very high concentration within the blood. Thus, where opticalmonitoring systems are used, the optical characteristics of water tendto obscure the characteristics of optical signals due to glucose withinthe bloodstream.

Furthermore, dry phase reagent test strips incorporating enzyme-basedcompositions are used extensively in clinical laboratories, physicians'offices, hospitals and homes to measure the resolution of thecompositions in the biological fluids. These strips have, for example,measured glucose, cholesterol, proteins, ketones, phenylalanine, orenzyme in blood, urine, or saliva. Measuring glucose resolution insamples of whole blood is a particularly common use. In fact, teststrips have become an everyday necessity for many of the nation'sseveral million people with diabetes.

Test strips are known that contain a testing reagent that turns adifferent shade of color, depending on the resolution of glucose in ablood sample that has been applied to the strips. The blood glucoseresolution is measured by inserting a strip into a meter that isbasically a reflectance photometer, which determines the resolution fromthe change in color caused by the reaction between the testing reagentand blood glucose. The testing reagent typically contains an enzyme,such as glucose oxidase, which is capable of oxidizing glucose toglucose acid lactone and hydrogen peroxide; an oxidizable dye; and asubstance having peroxidative activity, which is capable of selectivelycatalyzing oxidation of the oxidizable dye in the presence of hydrogenperoxide.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method forcalculating the resolution of blood glucose by the relationship betweenthe rising curve and the blood glucose resolution. The resolution of theblood glucose could be obtained from calculating these known valueswhich including the slope on the peak point, resistance, referenceresistance reference voltage, and the average peak value obtained fromcalculating the plurality of peak value after the pre-setting samplingtime.

It is still an object of the present invention to obtain the maximum ofthe peak value by using the property of the first differential of thepeak value being greater than zero.

It is yet object of the present invention to obtain the different heightof the peak value after the pre-setting different sampling time and takethem to make a mapping table.

It is a further object of the present invention to get the resolution ofblood glucose concentration according to the different voltage on themapping table.

According to the above-mentioned objects, the present invention providesa method of determining the resolution of the blood glucosecorresponding with the peak value of the rising curve. The peak value ofthe rising curve is the basis for determining the blood glucoseresolution in the present invention. The resolution of the blood glucosecould be obtained from calculating the given values, which including theslope on the peak point, resistance of the determining circuit,reference resistance and reference voltage and the average peak valueobtained from calculating the plurality of peak value after thepre-setting sampling time. Furthermore, the mapping table can be createdby recording the variable peak value according to the variablepre-setting sampling time, and correspond to the mapping table to obtainthe different resolution of blood glucose under the different outputtedvoltage.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same becomesbetter understood by reference to the following detailed description,when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram showing the peak value to determine theresolution of the blood glucose in accordance with a method disclosedherein;

FIG. 2 is a schematic diagram showing the relationship between the therising curve and the operation amplifier in accordance with a methoddisclosed herein;

FIG. 3 is a flow chart showing the steps for determining the resolutionof the blood glucose by using the peak value in accordance with a methoddisclosed herein;

FIG. 4 is a schematic diagram showing the rising curve of the bloodglucose resolution in accordance with a method disclosed herein; and

FIG. 5 is a schematic diagram showing the rising curves for thedifferent blood glucose resolution solution in accordance with a methoddisclosed herein.

DESCRIPTION OF THE INVENTION

An appropriate and preferred embodiment will now be described in thesection. It should be noted, however, that this embodiment is merely anexample and can be variously modified without departing from the scopeof the present invention. The present invention provides a performancemethod described as follow:

Firstly, the blood glucose solution is placed on the test strip with thetest reagent or catalyst such as enzyme, wherein the test reagent willreacted with the blood glucose solution to generate the oxidationreduction reaction to generate an analog source. Then, the analog sourceis inputted into a determining circuit of the determining meter totransfer into a treatment device to transfer the digital signal from theanalog source, and then outputting the digital signal to a displayapparatus.

Referring to FIG. 1, a schematic diagram showing the steps of the methodto determine the blood glucose resolution by utilizing the peak value.Firstly, with reference number 0 denotes the analogy source, whichgenerated from the chemical reaction between the blood glucose solutionand the test reagent with the enzyme such as catalyst; then, analogysource is inputted into a treatment device 12 to transfer the analogysource and is outputted into a display apparatus 14, wherein thetreatment device comprises an OP (operational amplifier 12A) with atleast one resistor, when the blood glucose resolution is getting higher,the resistance is also getting higher. Then, the analogy source istransferred into the AFE (analog front end) 12B. The analog source istransferred into the digital signal when the analog source s transferredto the AFE 12B, wherein the AFE 12B can be ADC (analog to digitalconverting system). Next, the digital signal is communicated into theMCU (microprocessor control unit) 12C to treat. Thereafter, the digitalsignal is outputted in the display apparatus 14. The diagram in thedisplay apparatus 14 is a curve diagram.

FIG. 2 is schematic diagram illustrating the relationship between therising curve of blood glucose resolution and the operational amplifier.After the blood glucose solution reacting with the test reagent toproduct the analogy signal source, the height of the curve is determinedon the blood glucose concentration and the resistance, the resistanceincreasing with the increase of the blood glucose concentration. Afterthe analogy signal source being transferred into operation amplifier,the analogy signal source will be transformed and transferred out as theoutputted voltage (V_(out)) from these known values, the slope on thepeak point, the resistance (R_(G)) in the operation amplifier, thereference resistance (R_(f)) and the reference voltage (V_(ref)).

FIG. 3 is schematic diagram illustrating the flow steps of getting theresolution of the blood glucose concentration by the peak value. In thisfigure, step 20 means that the blood glucose solution has a chemicalreaction by reacting with the catalyst to product the analogy signalsource, the chemical reaction may be an oxidation reduction reaction.Then, step 22 treat the analogy signal source and product a wavediagram. And then, at step 24, getting the maximum value of the wavediagram after the pre-setting sampling time. In the firstly preferredembodiment of the present invention, the average peak value could beobtained at step 26A by calculating the plurality of peak value afterthe pre-setting sampling time. And at step 26B, the method would get theresolution of the blood glucose concentration by the average peak value.Furthermore, in the other preferred embodiment, at step 28A, the methodof the present invention could make the plurality of peak value be amapping table which shows the relationship between the blood glucoseconcentration and the outputted voltage. And, at step 28B, the method ofthe present invention could calculate the resolution of the bloodglucose concentration by obtaining the outputted voltage value of anunknown blood glucose solution and looking into the mapping table.

FIG. 4 is schematic diagram illustrating the rising curve of the bloodglucose concentration. From the FIG.4, the present invention will getthe peak value after the pre-setting sampling time from the property ofthe first differential is larger than zero, y(t₁)−y(t₀)>0, which is thedifference between the first time (t₁) and the initial time (t₀) and itis larger than zero. With reference to the FIG. 4, in the firstlypreferred embodiment of the present invention, the average peak valuecould be obtained by adding and averaging the plurality of peak valueafter the pre-setting sampling time. From calculating the average peakvalue, the slope of the peak point, resistance, reference resistance andreference voltage, the method can get the resolution of the bloodglucose concentration.

FIG. 5 is schematic diagram illustrating the rising curves of thedifferent concentrations of the blood glucose solutions. In the FIG. 5,curves C1, C2 and C3 mean the different blood glucose concentrations. Asthe same, from the property of the first differential is larger thanzero, the method of the present invention get the peak value of thecurve and make a mapping table of the outputted voltage and bloodglucose concentration from the plurality of peak value. Therefore, themethod of calculating the real resolution of the blood glucoseconcentration is to obtain the outputted voltage value of an unknownblood glucose solution and look into the mapping table.

While this invention has been described with reference to illustrativeembodiments, the description is not intended being construed in alimiting sense. Various modifications and combinations of theillustrative embodiments, as well as other embodiments of the invention,will be apparent to persons skilled in the art upon reference to thedescription. It is therefore intended that the appended claims encompassany such modifications or embodiments.

1. A method for determining a resolution of blood glucose, comprising:obtaining an analog signal source from a blood glucose solution beingapplied to an amplifier circuit which includes a reference resistance;transforming said analog signal source into a digital signal;transmitting said digital signal with a rising curve to obtain anapproximate local maximum value of said rising curve; and determiningsaid resolution of blood glucose according to said approximate localmaximum value.
 2. The method according to claim 1, wherein said analogsignal source is generated at least in part, in response to applicationof the blood glucose solution on a test strip having catalyst.
 3. Themethod according to claim 2, wherein said analog signal source isgenerated at least in part, on an oxidation reduction reaction occurringin response to said application of said test strip.
 4. The methodaccording to claim 1, wherein said transforming said analog signalsource includes transmitting said analog signal source through an analogfront end (AFE).
 5. The method according to claim 1, wherein saidapproximate local maximum value being the difference between a firsttime (t₁) and an initial time (t₀) and said difference being larger thanzero. 6-15. (canceled)
 16. A method for determining a resolution ofblood glucose, comprising: receiving a blood glucose solution forreaction on a test strip having an enzyme to produce an analog signalsource; transmitting said analog signal source into a measurementcircuit; transforming said analog signal source into a digital signal;outputting said digital signal with a rising curve; determining anapproximate local maximum value of said rising curve; and making amapping table of said approximate local maximum value and an outputtedvoltage.
 17. The method according to claim 16, and further comprising:producing said analog signal source at least in part in response to anoxidation reduction reaction.
 18. The method according to claim 16,wherein said transforming said analog signal source further comprisestransmitting said analog signal source through an analog front end(AFE).
 19. The method according to claim 16, wherein said measuringcircuit includes a resistance.
 20. The method according to claim 16,wherein said measuring circuit includes a reference resistance.
 21. Themethod according to claim 16, wherein said measuring circuit includes areference voltage.
 22. The method according to claim 16, wherein saidoutputted voltage is determined by said reference voltage.
 23. Anapparatus comprising: an amplifier circuit operable to receive an analogsignal corresponding to a blood glucose reaction; a transforming circuitoperable to transform an amplified analog signal from said amplifiercircuit to a digital signal; and a control unit operable to determine aresolution of blood glucose according to an approximate local maximumvalue of a rising curve, wherein said rising curve corresponds to saiddigital signal.
 24. The apparatus of claim 23, wherein said analogsignal comprises a signal generated by a chemical reaction in responseto placing a blood glucose solution a test strip, wherein said teststrip comprises a catalyst.
 25. The apparatus of claim 24 wherein saidchemical reaction comprises an oxidation reduction reaction.
 26. Theapparatus of claim 25, wherein said transforming circuit comprises ananalog front end (AFE).
 27. The apparatus of claim 23, wherein saidapproximate local maximum value comprises a difference between a firsttime and an initial time, wherein said difference comprises a valuelarger than zero.
 28. The apparatus of claim 23, wherein said controlunit is further operable to determine said approximate local maximumvalue by calculating an average approximate local maximum value of aplurality of approximate local maximum values after a pre-settingsampling time.
 29. The apparatus of claim 23, wherein said controllerunit is further operable to provide a mapping table of a voltagecorresponding to said digital signal and a plurality of approximatelocal maximum values from a plurality of said rising curves.
 30. Asystem comprising: means for receiving an analog signal corresponding toa blood glucose reaction; means for transforming the amplified analogsignal to a digital signal; and means for determining a resolution ofblood glucose according to an approximate local maximum value of arising curve, wherein said rising curve corresponds to said digitalsignal.
 31. The system of claim 30, wherein said analog signal comprisesa signal generated by a chemical reaction in response to placing a bloodglucose solution a test strip, wherein said test strip comprises acatalyst.
 32. The system of claim 31, wherein said chemical reactioncomprises an oxidation reduction reaction.
 33. The system of claim 25,wherein said means for transforming comprises an analog front end (AFE).34. The system of claim 30, wherein said approximate local maximum valuecomprises a difference between a first time and an initial time, whereinsaid difference comprises a value larger than zero.
 35. The system ofclaim 30, wherein said means for determining if further operable todetermine said approximate local maximum value by calculating an averageapproximate local maximum value of a plurality of approximate localmaximum values after a pre-setting sampling time.
 36. The system ofclaim 35, wherein said means for determining is further operable toprovide a mapping table of a voltage corresponding to said digitalsignal and a plurality of approximate local maximum values from aplurality of said rising curves.
 37. An apparatus comprising: a teststrip operable to produce an analog signal in response to a reactionwith a blood glucose solution; a measuring circuit operable to receivesaid-analog signal; a transforming circuit operable to transform saidanalog signal into a digital signal; a controller unit operable tocalculate an average approximate local maximum value on a point of arising curve of said digital signal after a pre-setting sampling time;and wherein said controller unit is further operable to calculate aresolution of blood glucose according to said average approximate localmaximum value.
 38. The apparatus of claim 37, wherein said test stripcomprises a catalyst.
 39. The apparatus of claim 37, wherein saidreaction comprises an oxidation reduction reaction.
 40. The apparatus ofclaim 37, wherein said measuring circuit comprises a resistance, areference resistance and a reference voltage.
 41. The apparatus of claim37, wherein said transforming circuit is further operable to transfersaid analog signal through an analog front end (AFE).
 42. The apparatusof claim 37, wherein said approximate local maximum value comprises adifference between said digital signal at a first time and at an initialtime, wherein said difference comprises a value larger than zero. 43.The apparatus of claim 37, wherein said control unit is further operableto determine said resolution of blood glucose based at least in partsaid resistance, said reference resistance and said reference voltage.